1. Field of the Invention
The invention relates in general to a power converter, and more particularly to a high voltage gain power converter for converting an input voltage to an output voltage with a higher voltage level.
2. Description of the Related Art
The boost power converters have been widely used in many applications, such as the frond-end stage for a battery source, the DC back-up energy system for an uninterruptible power supply (UPS), and solar energy sources. The boost converter is sometimes called a step-up converter since it steps up the source voltage.
Conventionally, the boost converter includes an inductor, a power switch, a diode, and a capacitor. The boost converter is able to achieve high voltage gain when it operates in heavy duty cycle for the power switch. However, its voltage gain is limited to about five due to the losses of the circuit parasitic components in practice.
To increase the voltage gain, a cascade or a coupled-inductor schemes can be used instead. The former scheme was proposed in several IEEE papers and the latter scheme is disclosed in U.S. Pat. Nos. 8,392,124 and 8,386,1096, issued to Wai et al. However, the high voltage gain can be obtained at the cost of raising the circuit complexity.
Thus, there is a need for exploring a higher voltage gain with a simple power converter configuration and operating with a smaller duty cycle.